Method of manufacturing flat plate microlens and flat plate microlens

ABSTRACT

A large number of microscopic recess portions are formed on a surface of a glass substrate in a single dimension or two dimensions by conducting a wet etching through a mask. The large number of microscopic recess portions are aligned densely by again conducting the wet etching but not through the mask. A separating agent is applied upon the surface of the glass substrate and a light-curable or heat-curable resin material of high refractive index is applied thereon. The high refractive index resin material is cured, after piling a first glass substrate upon the high refractive index resin material so as to extend the high refractive index resin material thereon. The high refractive index resin material which is cured and the first glass substrate are separated from the glass substrate, and a low refractive index resin material is applied on the high refractive index resin material which is cured on the first glass substrate. The low refractive index resin material is cured, after piling a second glass substrate on the low refractive index resin material so as to extend the low refractive index resin material thereon.

BACKGROUND OF THE INVENTION

The present invention relates to a method for manufacturing a planarmicro-lens for use in a liquid crystal display element and so on, andrelates to a planar micro-lens being characterized by the lens materialthereof.

DESCRIPTION OF PRIOR ART

A liquid crystal display element is used in a projector television(PTV). In this liquid crystal display element, wherein a liquid crystalis put into a gap defined between two (2) pieces of glass plates, a TFT(thin film transistor) is formed from amorphous silicon and/orpolysilicon, upon a surface of each of site glass plates facing to theliquid crystal, corresponding to each of pixels.

And, in the PTV using a penetrative type of liquid crystal displayelement therein, an illumination light is irradiated from a xenon lampor a metal halide lamp, etc., upon the liquid crystal display element,so that it penetrate through pixel openings of the liquid crystaldisplay element to an exit side, thereby projecting a picture or videoimage formed on the liquid crystal display element through a projectionlens onto a screen.

For brightening the above-mentioned projection picture throughcollecting or condensing the above-mentioned illumination light onto thepixel openings, so as to increase the ratio of the illumination lightpenetrating through the liquid crystal display element, a planarmicro-lens is connected or bonded on one of the two (2) pieces of glasssubstrates constructing the liquid crystal display element, at a sideupon which the illumination light is incident, so that the illuminationlight is condensed onto the pixel openings, and a method formanufacturing such planar micro-lens is known, as is disclosed, forexample, in Japanese Laid-Open Patent Hei 7-225303 (1995). Also, furthermethods are known, such as those disclosed in Japanese Laid-Open PatentHei 2-42401 (199), Japanese Laid-Open Patent Hei 2-116809 (1990), andU.S. Pat. No. 5,513,289.

Explanation of the manufacturing method of the planar micro-lensdisclosed in the Japanese Laid-Open Patent Hei 7-225303 is as below,explained with reference to to FIGS. 20(a) through (h).

First, as shown in FIG. 20(a), a light sensitive film is formed on asurface of the substrate, and an electron beam is irradiated on thelight sensitive film so as to form the lens portion, as shown in FIG.20(b), thereby producing a master disc of the micro-lens array.

Next, as shown in FIG. 20(c), upon the surface of the master disc of themicro-lens array is laminated nickel or the like through an electrocastmethod, and further, as shown in FIG. 20(d), the laminated body isseparated or removed from the master disc of the micro-lens array,thereby producing a stamper.

Then, as shown in FIG. 20(e), an ultraviolet ray curable resin is pouredinto recess portions of the stamper, and as shown in FIG. 20(f), it isextended while being pushed down by a transparent substrate, and furtheras shown in FIG. 20(g), the ultraviolet ray curable resin is cured, andthereafter as shown in FIG. 20(h), the ultraviolet ray curable resin isseparated from the stamper together with the transparent substrate.

Then, upon the surface of the separated transparent substrate, on whichthe lens portions are formed from the ultraviolet ray curable resin, acover glass is fitted to be bonded on it, by pouring an adhesive resinof low refraction index to be contained between the facing surfacesthereof, thereby forming the planar micro-lens.

The lens portions are formed by means of irradiating an electron beamupon a resist in the above-mentioned method, however it is difficult toform a microscopic lens by this method with high precision or accuracy.

Also, for the planar micro-lens to be installed within a liquid crystaldisplay device, it is desirable to be of a dense type, in which a largenumber of the lens portions are aligned closely without gaps betweenthem in the plane view thereof, however it is difficult to produce suchthe dense micro-lens array through such a conventional manufacturingmethod as that mentioned above.

Further, for manufacturing the liquid crystal display device, it is alsonecessary to form elements or components such as transparent electrodes,an orientation film, a black matrix, etc., on a surface of theabove-mentioned cover glass facing to the liquid crystal. Since thesteps for the forming of those elements must be conducted under heating,it is therefore determined that resin materials forming the lens and theadhesive layers should not be such ones that may be subject to thermalcracking and/or thermal deformation and decreases of transparencythereof, and in the Japanese Laid-Open Patent Hei 7-225303 (1995) arelisted various materials being commercially available for use as resinsheat-resistant against temperatures of 150° C. or more. However, inactual practice, by taking the temperature for forming the transparentelectrodes and the orientation film with a spattering method, etc., intoconsideration, heat-resistance against 150° C. or more is not greatenough resistance, since there can be easily caused a change of color(i.e., transparent material changed in color to yellow), separation,cracks, dimness, etc., therefore at least a heat-resistance totemperatures of 180° C. or more is required for the resin materialhaving high refraction index, which is used as the lens portion inparticular.

DISCLOSURE OF THE INVENTION

In accordance with the present invention, for dissolving such problemsof the conventional arts as those mentioned above, a first object is toprovide a method for manufacturing a planar micro-lens, with whichmicroscopic lens portions can be formed on the surface of a glasssubstrate with high precision or accuracy, and a second object is toprovide a planar micro-lens having a superior hear-resistance thereof.

For achieving the first object, according to the present invention,there are provided methods relating to the present claims 1 through 3,assuming that each of them is based upon a method for manufacturing aplanar micro-lens, having a high refractive index resin material and alow refractive index resin material, being laminated in layers within aregion defined between a first glass substrate and a second glasssubstrate, wherein microscopic spherical surfaces or microscopiccylindrical surfaces are aligned on a boundary surface of the two kindsof the resin materials in a single dimension or two dimensions, whereinthe method for manufacturing a planar micro-lens defined in claim 1comprises the following first through sixth steps:

(First step)

a step for forming a large number of microscopic recess portions formingcylindrical or spherical surfaces on a surface of a glass substrate in asingle dimension or two dimensions, by conducting a wet etching througha mask upon the surface of the glass substrate as a forming die;

(Second step)

a step for aligning the large number of the microscopic recess portionsdensely, by again conducting the wet etching upon the surface of theglass substrate as the forming die on which the microscopic recessportions are formed in the first step, but not through the mask;

(Third step)

a step for applying a separating agent upon the surface of the glasssubstrate as the forming die having the microscopic recess portionsaligned densely being formed in the second step, and further forapplying a light-curable or heat-curable resin material of highrefractive index thereon;

(Fourth step)

a step for curing the high refractive index resin material, after pilinga first glass substrate upon the high refractive index resin materialwhich is applied to the glass substrate as the forming die in the thirdstep, so as to cause the high refractive index resin material to extendon the surface thereof;

(Fifth step)

a step for separating the high refractive index resin material which iscured in the fourth step and the first glass substrate from the glasssubstrate as the forming die, and for applying a low refractive indexresin material on the high refractive index resin material which iscured on the first glass substrate; and

(Sixth step)

a step for curing the low refractive index resin material, after pilinga second glass substrate on the low refractive index resin materialwhich is applied to the high refractive index resin material in thefifth step so as so cause the low refractive index resin material toextend on the surface thereof.

Also, the method for manufacturing a planar micro-lens, defined in claim2, comprises the following first through seventh steps:

(First step)

a step for forming a large number of microscopic recess portions formingcylindrical or spherical surfaces on a surface of a glass substrate in asingle dimension or two dimensions, by conducting a wet etching througha mask upon the surface of the glass substrate as a forming die;

(Second step)

a step for aligning the large number of the microscopic recess portionsdensely, by again conducting the wet etching upon the surface of theglass substrate as the forming die on which the microscopic recessportions are formed in the first step, but not through the mask;

(Third step)

a step for transferring a surface configuration of the glass substrateas the forming die, upon which the large number of the microscopicrecess portions are formed densely in the second step, onto a reverseforming die made of nickel and so on;

(Fourth step)

a step for applying a separating agent upon the surface of the reverseforming die being formed in the third step, and further for applyingthereon a light-curable or heat-curable resin material of low refractiveindex;

(Fifth step)

a step for curing the low refractive index resin material, after pilinga second glass substrate upon the low refractive index resin materialwhich is applied to in the fourth step so as to cause the low refractiveindex resin material so extend on the surface thereof;

(Sixth step)

a step for separating the low refractive index resin material which iscured in the fifth step and the second glass substrate from the reverseforming die, and for applying a high refractive index resin material onthe low refractive index resin material which is cured on the secondglass substrate; and

(Seventh step)

a step for curing the high refractive index resin material, after pilinga first glass substrate on the high refractive index resin materialwhich is applied to the low refractive index resin material in the sixthstep so at to cause the high refractive index resin material to extendon the surface thereof.

Further, the method for manufacturing a planar micro-lens, defined inclaim 3, comprises the following first through eighth steps:

(First step)

a step for forming a large number of microscopic recess portions formingcylindrical or spherical surfaces on a surface of a glass substrate in asingle dimension or two dimensions, by conducting a wet etching througha mask upon the surface of the glass substrate as a forming die;

(Second step)

a step for aligning the microscopic recess portions densely, by againconducting the wet etching upon the surface of the glass substrate asthe forming die on which the large number of the microscopic recessportions are formed in the first step, but not through the mask;

(Third step)

a step for transferring a surface configuration of the glass substrateas the forming die, upon which the large number of the microscopicrecess portions are formed densely in the second step, onto a firstreverse forming die made of nickel and so on;

(Fourth step)

a step for transferring a surface configuration of the first reverseforming die, which is produced in the third step, onto a second reverseforming die made of nickel and so on;

(Fifth step)

a step for applying a separating agent upon the surface of the secondreverse die being formed in the fourth step, and further for applyingthereon a light-curable or heat-curable resin material of highrefractive index;

(Sixth step)

a step for curing the high refractive index resin material, after pilinga first glass substrate upon the high refractive index resin materialwhich is applied to in the fifth step so as to cause the high refractiveindex resin material to extend on the surface thereof;

(Seventh step)

a step for separating the high refractive index resin material which iscured in the sixth step and the first glass substrate from the secondreverse forming die, and for applying a low refractive index resinmaterial on the high refractive index resin material which is cured onthe first glass substrate; and

(Eighth step)

a step for curing the low refractive index resin material, after pilinga second glass substrate on the low refractive index resin materialwhich is applied to the high refractive index resin material in theseventh step so at to cause the low refractive index resin material toextend on the surface thereof.

For achieving the second object of the present invention, as defined inthe present claims 4 through 12, provided is a planar micro-lens havinga high refractive index resin material and a low refractive index resinmaterial, being laminated in layers within a region defined between two(2) pieces of glass substrates, wherein microscopic cylindrical surfacesor microscopic spherical surfaces are aligned on a boundary surface ofthe two kinds of resin material in a single dimension or two dimensions,and said high refractive index resin material is comprised of a resinhaving thiol bonding (R—S—H) or a resin having sulfide bonding (R—S—R′),or a resin being expressed by a general equation, (R′—S—R—S—R—S—R′), asa main ingredient,

where S is sulfur, H hydrogen, R any one of cyclic unsaturatedhydrocarbon, cyclic saturated hydrocarbon, straight chain-likeunsaturated hydrocarbon and straight chain-like saturated hydrocarbon,and R′ any one of organic compounds having acryloyl group, methacryloylgroup, epoxy group, isocyanate group, amino group, acyl group, carboxylgroup, alkoxylil group, vinyl group.

The main ingredient which forms said high refractive index resinmaterial is properly a polymer, obtained from monomers indicated by thefollowing structural formulae as starting materials thereof;

(X indicates hydrogen or methyl group, and n an integer from 0 to 2)

where in the formula, R₁ indicates

CH₂═CHCOOCH₂CH₂— or CH₂═C(CH₃)COOCH₂CH₂— and Y—R₂—S—R₂— or—R₂—S—(R₂Z)—_(m)R₂—S—R₂— (however, R₂ indicates alkylene group, while Zoxygen atom or sulfur atom. Also, m indicates an integer from 0 to 3)

(in the formula, R indicates —CH₂—, —CH₂CH₂—, or —CH(CH₃)CH₂—)

Also, the low refractive index resin material which is laminated withthe high refractive index resin material is properly any one of resinsof fluorine group, resins of acryl group, and resins of epoxy group.

Also, any one of boundary surfaces between said glass substrate and thehigh refractive index resin material, between the glass substrate andthe low refractive index resin material, and between the high refractiveindex resin material and the low refractive index resin material, iscoupled through a coupling agent, thereby increasing the bonding powertherebetween, as well as effectively preventing any change in color(i.e.: yellow coloring) due to invasion of oxygen into the boundarysurfaces. Further, the coupling agent can be comprised ofγ-glycidepropyl-trimethoxysilane or γ-mercaptpropyl-trimethoxysilane.

Also, it is possible to make the high refractive index resin materialcontain a curing agent of the thiol group. If it contains the curingagent of the thiol group, because an oxide in the main agent is reducedby the thiol, because an impurity which ought to be oxidized and coloredis reduced due to the existence of the thiol, and further because itcannot take on a coloring resonant structure due to addition of thethiol, it is possible to prevent coloration of the high refractive indexresin material. The curing agent of the thiol group may comprise, forexample, pentaerithritol-tetrakisthiopropionate indicated by thefollowing equation (formula 10), or trihydroxyethyl-isocyanate βmercaptpropionic acid, as indicated by the following equation (formula11):

Formula 10

(HSCH₂CH₂COOCH₂)₄C

Further, it is possible to make the high refractive index resin materialcontain a curing promotion agent other than the curing agent of thethiol group. The curing promotion agent may comprise, for example,dibutyltin-dilaurate, as indicated by the following formula 12:

Formula 12

[CH₂(CH₂)₃]₂Sn[OOC(CH₂)₁₀CH₃]₂

Also, as the glass substrate used in constructing the planar micro-lens,though its type is not particularly restricted, employed may be one madefrom a quartz glass, a low expansive crystal glass, or a borosilicateglass.

As the low expansive crystal glass can be used “Neoceram (®)” by NipponDenki Glass Co., Ltd., (66SiO₂22Al₂O₃4LiO₂2ZrO₂2TiO₂) or “Vycor” byCorning Inc., (96SiO₂3B₂O₃1Al₂O₃).

Further, as examples of the composition of the borosilicate glass, thefollowing are preferable:

(Composition 1)

SiO₂: equal to or greater than 45 mass % and equal to or less than 75mass %;

B₂O₃: equal to or greater than 8.0 mass % and equal to or less than 19.0mass %;

BaO: equal to or greater than 4.2 mass % and equal to or less than 14mass %;

MO (M being a metal of 2-valence other than Ba): equal to or greaterthan 10 mass % and equal to or less than 30 mass %;

R₂O (R being a metal of 1-valence): equal to or less than 10 mass %;

(Composition 2)

SiO₂: equal to or greater than 45 mass % and equal to or less than 75mass %;

B₂O₃: equal to or greater than 9.5 mass % and equal to or less than 12.5mass %;

BaO: equal to or greater than 4.2 mass % and equal to or less than 14mass %;

MO (M being a metal of 2-valence other than Ba): equal to or greaterthan 10 mass % and equal to or less than 30 mass %;

R₂O (R being a metal of 1-valence): equal to or less than 10 mass %;

(Composition 3)

SiO₂: equal to or greater than 45 mass % and equal to or less than 75mass %;

B₂O₃: equal to or greater than 8.0 mass % and equal to or less than 19.0mass

BaO: equal to or greater than 4.2 mass % and equal to or less than 14mass %;

MO (M being a metal of 2-valence other than Ba): equal to or greaterthan 10 mass % and equal to or lets than 30 mass %;

R₂O (R being a metal of 1-valence): equal to or less than 1 mass %;

(Composition 4)

SiO₂: equal to or greater than 45 mass % and equal to or less than 75mass %;

B₂O₃: equal to or greater than 8.0 mass % and equal to or less than 19.0mass %;

BaO: equal to or greater than 4.2 mass % and equal to or less than 10mass %;

MO (M being a metal of 2-valence other than Ba): equal to or greaterthan 10 mass % and equal to or less than 30 mass %;

R₂O (R being a metal of 1-valence): equal to or less than 10 mass %;

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view showing a step in the manufacture of a planarmicro-lens according to the present invention;

FIG. 2 is a view showing a step in the manufacture of the same planarmicro-lens;

FIG. 3(a) is a view showing a step in the manufacture of the same planarmicro-lens, and FIG. 3(b) is a plane view of FIG. 3(a);

FIG. 4 is a view showing a step in the manufacture of the same planarmicro-lens;

FIG. 5 is a view showing a step in the manufacture of the same planarmicro-lens;

FIG. 6 is a view showing a step in the manufacture of the same planermicro-lens;

FIG. 7 is a view showing a step in the manufacture of the same planarmicro-lens;

FIG. 8 is a view showing a step in the manufacture of the same planarmicro-lens;

FIG. 9 is a cross-sectional view of the planar micro-lens according tothe present invention;

FIG. 10 is a view showing another embodiment of a step in themanufacture of a planar micro-lent according to the present invention;

FIG. 11 is a view showing another embodiment of a step in themanufacture of the same planar micro-lens according to the presentinvention;

FIG. 12 is a view showing another embodiment of a step in themanufacture of the same planar micro-lens according to the presentinvention;

FIG. 13 is a view showing another embodiment of a step in themanufacture of the same planar micro-lens according to the presentinvention;

FIG. 14 is a view showing another embodiment of a step in themanufacture of the same planar micro-lens according to the presentinvention;

FIG. 15 is a view showing another embodiment of a step in themanufacture of the same planar micro-lens according to the presentinvention;

FIG. 16 is a view showing another embodiment of a step in themanufacture of the same planar micro-lens according to the presentinvention;

FIG. 17 is a view showing another embodiment of a step in themanufacture of the same planar micro-lens according to the presentinvention;

FIG. 18 is a view showing another embodiment of a step in themanufacture of the same planar micro-lens according to the presentinvention;

FIG. 19 is a view showing another embodiment of a step in themanufacture of the same planar micro-less according to the presentinvention;

FIGS. 20(a) to (h) are views showing steps in the manufacture of aconventional planar micro-lens.

In the above figures, reference numeral 1 indicates a glass substrate tobe a forming die, 2 indicates a mask, 3 indicates recess portions, 4indicates a layer of a separating agent, 5 indicates a high refractiveindex resin material, 6 indicates a first glass substrate, 7 indicates alow refractive index resin material, 8 indicates a second glasssubstrate, 11 indicates a reverse forming die (a first reverse formingdie), and 12 indicates a second reverse forming die.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments according to the present invention will befully explained with reference to the attached drawings. Herein, FIGS. 1through 9 are views showing steps of the manufacture of a planarmicro-lens according to the present invention wherein, according to thepresent invention, as first shown in FIG. 1, upon the surface of a glasssubstrate 1 to be a forming die is piled up a mask 2, on which a largenumber of small bores 2 a are formed, and next the surface thereof beingcovered with the mask 2 is dipped into an etchant of HF (hydrogenfluoride) in order to conduct wet etching thereon.

Since the wet etching exhibits a pattern of isotropic etching, as shownin FIG. 2, recess portions 3 of roughly hemispherical shape are formedin single or one (1) dimensional or two (2) dimensional manner, onportions corresponding to the small bores 2 a. However, the recessportions 3 may be gutters of semicircular shape in the cross-sectionthereof. In this instance, lenticular lenses are formed therein.

Next, the mask 2 is removed, and the surface on which the recessportions 3 are formed is treated, again, with wet etching. With thisetching, as shown in FIG. 3(a), the glass substrate 1 to be the formingdie comes to be thin in the thickness thereof, and the surface thereof,including the recess portions thereon, is etched, equally or uniformly,therefore the recess portion of the hemispherical shape comes to beflattened or compressed in form, and as shown from a plane view pointthereof in FIG. 3(b), the recess portions are closely formed or alignedwith no gap therebetween.

Though in FIG. 3(b) is shown a condition that the recess portions 3 areformed closely in a honeycomb-like (hexagonal) shape, they may be formedclosely in a quadrilateral-like shape depending upon the arrangementthereof.

Upon the surface of the glass substrate 1 on which the recess portionsare arranged through the above-mentioned etching, as shown in FIG. 4, alayer 4 of a separating of materials of fluorine group or silicon groupis formed. In a method for forming the separating agent layer 4, thematerial thereof is baked after it is applied onto the surface of theglass substrate 1 through, for example, a spin-coating method, a dippingmethod, a method of adsorbing the material evaporated onto the surfaceof the glass substrate, or a method of adsorbing the material onto thesurface by dipping into a solution of the material, etc.

After this, as shown in FIG. 5, upon the surface on which is formed theseparating agent layer 4 is applied a light-curable or heat-curable highrefractive index resin material 5, and further as shown in FIG. 6, afirst glass substrate 6 is pushed down on the high refractive indexresin material 5, thereby expanding or spreading the high refractiveindex resin material 5 thereon. Herein, it is preferable to form a filmof a coupling agent on the surface of the first glass substrate 6,facing to the high refractive index resin material 5, or to remove anyresidue of the separating agent, which will be shifted a little bit onthe surface of the high refractive index resin material 5, whenseparating, by rinsing it away with a solvent.

In the manner as mentioned above, under the condition that the firstglass substrate 6 is layered over the high refractive index resinmaterial 5, the high refractive index resin material 5 is cured by anirradiation of ultraviolet rays or by heating, then the first glasssubstrate 6 and the high refractive index resin material 5 cured inconvex lens-like forms are separated from the glass substrate 1 as shownin FIG. 7.

Next, as shown in FIG. 8, a light-curable or heat-curable low refractiveindex resin material 7 is applied upon the high refractive index resinmaterial 5 being cured in the convex lens-like forms. This lowrefractive index resin material 7 has a function as an adhesive.

And further, as shown in FIG. 9, after pressing a second glass substrate8 on the low refractive index resin material 7, thereby spreading itthereon, the low refractive index resin material 7 is cured, and finallythe first glass substrate 6 and the second substrate 8 are ground orpolished to be of a predetermined thickness depending upon the necessitythereof, thereby completing the planar micro-lenses.

It is preferable that a film of the coupling agent is formed on theboundary surface between the high refractive index resin material 5 andthe low refractive index resin material 7, and/or between the lowrefractive index resin material 7 and the second glass substrate 8.

FIGS. 10 to 14 are views showing the manufacturing steps of the planarmicro-lens according to a second embodiment, and in the secondembodiment, since the steps leading up to the formation of the recessportions, formed closely on the surface of the glass substrate 1, aresame as those in the first embodiment, a second recitation of thesesteps is therefore omitted.

In the second embodiment, as shown in FIG. 10, the surface configurationof the glass substrate 1, on which the recess portions are arrangedclosely, is copied or transferred onto a reverse forming die 11 ofnickel or the like, through an electric casting, etc., and then the samecoating of the separating agent is applied thereon as in the firstembodiment.

Next, as shown in FIG. 11, upon the reverse forming die 11 is applied alight-curable or heat-curable low refractive index resin material 7, andfurther, as shown in FIG. 12, after a second glass substrate 8 islayered thereon so as to spread resin 7 thereby, the low refractiveindex resin material 7 is cured. Next, the cured low refractive indexresin material 7 and the second glass substrate 8 are separated from thereverse forming die 11, and as shows in FIG. 13, a high refractive indexresin material 5 is applied onto the cured low refractive index resinmaterial 7. Further, as shown in FIG. 14, after the first glasssubstrate 6 is layered thereon, so as to spread resin 5 thereby, thehigh refractive index resin material 5 may be cured.

FIGS. 15 to 19 see views showing the manufacturing steps of the planarmicro-lens according to a third embodiment, and also in the thirdembodiment, since the steps leading up to the formation of the recessportions, formed closely on the surface of the glass substrate 1, aresame as those in the first embodiment, a further recitation of thesesteps is omitted.

In the third embodiment, the surface configuration of the reverseforming die 11 of nickel or the like is copied or transferred onto asecond reverse forming die 12 of nickel or the like, as shown in FIG.15, and the coating of the separating agent is applied, in the samemanner as in the first embodiment. Next, on this second reverse formingdie 12 is applied the light-curable or heat-curable high refractiveindex resin material 5, and then as shown in FIG. 16, the first glasssubstrate 6 is layered on the high refractive index resin material 5.After being extended thereby, the high refractive index resin material 5is cured, then the first glass substrate 6 and the high refractive indexresin material 5 cured in the convex lens-like shape are separated fromthe second reverse forming die 12 as shown in FIG. 17, and next as shownin FIG. 18, the light-curable or heat-curable low refractive resinmaterial 7 is applied on the high refractive index resin material 5cured in the convex lens-like shape. Further, as shown in FIG. 19, thesecond glass substrate 5 is pushed down on the low refractive indexresin material 7 so as to extend it thereon, and thereafter it is cured.

As was explained in the above, with the manufacturing method of theplanar micro-lens according to the present invention, it is possible tomanufacture the micro-lens array in which the lens portions are arrangedclosely without gaps between them, in the plane view thereof.

Further, taking the steps for manufacturing the liquid crystal displaydevice into consideration, it is necessary to use the special highrefractive index resin material and the low refractive index resinmaterial both being durable enough to withstand processing at a hightemperature of about 180° C. However, in general, such resins'separation qualities are poor. Because of this, they sometimes cannot beseparated from the die, or the die is damaged when they are separatedfrom them, therefore it is impossible to achieve good or qualifiedforming. However, according to the present invention, since theseparating agent is applied on the forming die, the resins can beseparated easily from the forming die, with no damage occurring to theforming die.

Also, those micro-lenses are formed in the concave-convex shape, beingvery minute or microscopic in the sizes thereof, such as from 10 μm toseveral tens of μm, however since it is possible to form a film of theseparating agent with an uniform thickness at a sub-micron scale, byapplying the separating agent with an appropriate concentration thereof,therefore it is possible to faithfully copy or transfer the minuteconcave-convex configuration of a master disc to be produced withprecision, accuracy and correctness, through the glass etching.

In particular, the separating agent of the fluorine group can bedissolved into an organic solvent, such as isobutane, etc. Thisseparating agent is convenient since it can be applied repeatedly, afterrinsing away the previous application of the separating agent from thesurface of the forming die, in particular in a case where the separationproperty thereof is decreased because a part of the separating agentfilm thereof is exfoliated or removed after repetitive using of theforming die.

Also, effects of the invention described in claim 1 can be listedincluding that the step of transferring onto the Ni stamper is notnecessitated, that there is no probability of change in the shape ordamage to the stamper in the step of manufacturing the stamper, andfurther that the glass master disc is cheaper than the Ni stamper.

Also, as an effect inherent to the invention described in claim 2,though many of the high refractive index resin materials shown in thepresent application are heat-curable resins, but ones beinglight-curable are difficult to obtain, it is very effective to use thereverse forming die made of Ni, etc., as described in claim 2, toovercome these challenges.

Further, as an effect inherent to the invention described in claim 3,since there are some resins which show large resistance when they areseparated even with use of the separating agent, the minuteconcave-convex formation of glass can be broken or damaged slightly whenthe resin is separated from the forming die, dependent upon the resin,however by using the stamper which is same as the glass master disc in amale and female relation, it is possible to suppress the breakage of thestamper.

Also, with the planar micro-lens according to the present invention, inthe planar micro-lens thereof, having a high refractive index resinmaterial and a low refractive index resin material, being laminated inlayers within a region defined between two (2) pieces of glasssubstrates, in which microscopic cylindrical surfaces or microscopicspherical surfaces are aligned on a boundary surface of the two kinds ofresin materials in a single dimension or two dimensions, by using theproposed, specific high refractive index resin materials, it is possibleto prevent the lens portions from being subject to deformation ordeterioration thereof even when they are exposed under the hightemperature of 180° C. or more, thereby obtaining the planar micro-lenswhile preserving a certain transparency thereof.

INDUSTRIAL APPLICABILITY

With the method for manufacturing the planar micro-lens and the planarmicrolens, according to the present invention, it is possible to providecomponents for a liquid crystal display element to be utilized in aprojection television (PTV).

What is claimed is:
 1. A method for manufacturing a planar micro-lens,having a high refractive index resin material and a low refractive indexresin material, being laminated in layers within a region definedbetween a first glass substrate and a second glass substrate, whereinmicroscopic cylindrical surfaces or microscopic spherical surfaces arealigned on a boundary surface of the high refractive index resinmaterial and the low refractive index resin material in a singledimension or two dimensions, said method comprising the following firstthrough sixth steps: (First step) a step for forming a large number ofmicroscopic recess portions forming cylindrical or spherical surfaces ona surface of a glass substrate in a single dimension or two dimensions,by conducting a wet etching through a mask upon the surface of the glasssubstrate as a forming die; (Second step) a step for aligning the largenumber of the microscopic recess portions densely, by again conductingthe wet etching upon the surface of the glass substrate as the formingdie on which die microscopic recess portions are formed in the firststep, but not through the mask; (Third step) a step for applying aseparating agent upon the surface of the glass substrate as the formingdie having the microscopic recess portions aligned densely, being formedin the second step, and further for applying a light-curable orheat-curable resin material of high refractive index thereon; (Fourthstep) a step for curing the high refractive index resin material, afterpiling a first glass substrate upon the high refractive index resinmaterial which is applied to the glass substrate as the forming die inthe third step so as to cause the high refractive index resin materialto extend on the surface thereof; (Fifth step) a step for separating thehigh refractive index resin material which is cured in the fourth stepand the first glass substrate from the glass substrate as the formingdie, and for applying a low refractive index resin material on the highrefractive index resin material which is cured on the first glasssubstrate; and (Sixth step) a step for curing the low refractive indexresin material, after piling a second glass substrate on the lowrefractive index resin material which is applied to the high refractiveindex resin material in the fifth step so as to cause the low refractiveindex resin material to extend on the surface thereof.
 2. A method formanufacturing a planar micro-lens, having a high refractive index resinmaterial and a low refractive index resin material, being laminated inlayers within a region defined between a first glass substrate and asecond glass substrate, wherein a large number of microscopiccylindrical surfaces or microscopic spherical surfaces are aligned on aboundary surface of the two kinds of the resin materials in a singledimension or two dimensions, said method comprising the following firstthrough seventh steps: (First step) a step for forming a large number ofmicroscopic recess portions forming cylindrical or spherical surfaces ona surface of a glass substrate in a single dimension or two dimensions,by conducting a wet etching through a mask upon the surface of the glasssubstrate as a forming die; (Second step) a step for aligning the largenumber of the microscopic recess portions densely, by again conductingthe wet etching upon the surface of the glass substrate as the formingdie on which the microscopic recess portions are formed in the firststep, but not through the mask; (Third step) a step for transferring asurface configuration of the glass substrate as the forming die uponwhich the large number of the microscopic recess portions are formeddensely in the second step, onto a reverse forming die made of nickel orthe like; (Fourth step) a step for applying a separating agent upon thesurface of the reverse forming die being formed in the third step, andfurther for applying thereon a light-curable or heat-curable resinmaterial of low refractive index; (Fifth step) a step for curing the lowrefractive index resin material, after piling a second glass substrateupon the low refractive index resin material which is applied to thereverse forming die in the fourth step so as to cause the low refractiveindex resin material to extend on the surface thereof; (Sixth step) astep for separating the low refractive index resin material which iscured in the fifth step and the second glass substrate from the reverseforming die, and for applying a high refractive index resin material onthe low refractive index resin material which is cured on the secondglass substrate; and (Seventh step) a step for curing the highrefractive index resin material, after piling a first glass substrate onthe high refractive index resin material which is applied to the lowrefractive index resin material in the sixth step so as to cause thehigh refractive index resin material to extend on the surface thereof.3. A method for manufacturing a planar micro-lens, having a highrefractive index resin material and a low refractive index resinmaterial, being laminated in layers within a region defined between afirst glass substrate and a second glass substrate, wherein a largenumber of microscopic cylindrical surfaces or microscopic sphericalsurfaces are aligned on a boundary surface of the two kinds of the resinmaterials in a single dimension or two dimensions, said methodcomprising the following first through eighth steps: (First step) a stepfor forming a large number of microscopic recess portions formingcylindrical or spherical surfaces on a surface of a glass substrate in asingle dimension or two dimensions, by conducting a wet etching througha mask upon the surface of the glass substrate as a forming die; (Secondstep) a step for aligning the microscopic recess portions densely, byagain conducting the wet etching upon the surface of the glass substrateas the forming die on which the large number of the microscopic recessportions are formed in the first step, but not through the mask; (Thirdstep) a step for transferring a surface configuration of the glasssubstrate as the forming die upon which the large number of themicroscopic recess portions are formed densely in the second step, ontoa first reverse forming die made of nickel or the like; (Fourth step) astep for transferring a surface configuration of the first reverseforming die, which is produced in the third step, onto a second reverseforming die; (Fifth step) a step for applying a separating agent uponthe surface of the second reverse forming die being formed in the fourthstep, and further for applying thereon a light-curable or heat-curableresin material of high refractive index; (Sixth step) a step for curingthe high refractive index resin material, after piling a first glasssubstrate upon the high refractive index resin material which is appliedto the second reverse forming die in the fifth step so as to cause thehigh refractive index resin material to extend on the surface thereof;(Seventh step) a step for separating the high refractive index resinmaterial which is cured in the sixth step and the first glass substratefrom the second reverse forming die, and for applying a low refractiveindex resin material on the high refractive index resin material whichis cured on the first glass substrate; and (Eighth step) a step forcuring the low refractive index resin material, after piling a secondglass substrate on the low refractive index resin material which isapplied to the high refractive index resin material in the seventh stepso as to cause the low refractive index resin material to extend on thesurface thereof.
 4. A planar micro-lens, having a high refractive indexresin material and a low refractive index resin material being laminatedin layers within a region defined between two (2) pieces of glasssubstrates, wherein microscopic cylindrical surfaces or microscopicspherical surfaces are aligned on a boundary surface of the two kinds ofthe resin materials in a single dimension or two dimensions, and saidhigh refractive index resin material is comprised of a resin havingthiol bonding (R—S—H) or a resin having sulfide bonding (R—S—R′), or aresin being expressed by a general equation, (R′—S—R—S—R—S—R′), where Sis sulfur, H hydrogen, R any one of cyclic unsaturated hydrocarbon,cyclic saturated hydrocarbon, straight chain-like unsaturatedhydrocarbon and straight chain-like saturated hydrocarbon, and R′any oneof organic compounds having acryloyl group, methacryloyl group, epoxygroup, isocyanate group, amino group, acyl group, carboxyl group,alkoxylil group, vinyl group.
 5. A planar micro-lens as defined is claim4, wherein the main ingredient which forms said high refractive indexresin material is a polymer obtained from the monomers indicated by thefollowing structural formulas as starting materials thereof:

(X indicates hydrogen or methyl group, and n an integer from 0 to 2)

where in the formula, R, indicates

CH₂═CHCOOCH₂CH₂— or CH₂═C(CH₃)COOCH₂CH₂— and Y—R₂—S—R₂— or—R₂—S—(R₂Z)—_(m)R₂—S—R₂— (however, R₂ indicates alkylene group, while Zoxygen atom or sulfur atom. Also, m indicates an integer from 0 to 3)


6. A planar micro-lens as defined in claim 4, wherein said lowrefractive index resin material is any one of resins of fluorine group,resins of acryl group, and resins of epoxy group.
 7. A planar micro-lensas defined in claim 4, wherein any one of boundary surfaces between saidglass substrate and the high refractive index resin material, betweenthe glass substrate and the low refractive index resin material, andbetween the high refractive index resin material and the low refractiveindex resin material, is coupled by means of a coupling agent.
 8. Aplanar micro-lens as defined in claim 7, wherein said coupling agent isγ-glycidepropyl-trimethoxysilane or γ-mercaptpropyl-trimethoxysilane. 9.A planar micro-lens an defined in claim 4, wherein said high refractiveindex resin material contains a curing agent of thiol group.
 10. Aplanar micro-lens as defined in claim 9, wherein said curing agent ofthiol group is pentaerithritol-tetrakisthiopropionate, as indicated bythe following equation (formula 10), or trihydroxyethyl-isocyanate βmercaptpropionic acid, as indicated by the following equation (formula11):   Formula 10 (HSCH₂CH₂COOCH₂)₄C


11. A planar micro-lens as defined in claim 9, wherein a curingpromotion agent is contained which is other than said curing agent ofthiol group.
 12. A planar micro-lens as defined in claim 11, whereinsaid curing promotion agent is dibutyltin-dilaurate, as indicated by thefollowing formula 12:   Formula 12 [CH₂(CH₂)₃]₂Sn[OOC(CH₂)₁₀CH₃]₂